DEV: Fix connections timeout in system test (#25835)

Why this change?

This regressed in 6e9fbb5bab because we
had a `request.xhr?` check before we decide to block requests. However,
there could not none-xhr requests which we need to block as well at the
end of each system test when `@@block_requests` is true.

This also reverts commit 6437f27f90.

lib/freedom_patches/debug_connection_queue.rb

@@ -1,40 +0,0 @@
-# frozen_string_literal: true
-
-if ENV["DEBUG_AR_CONNECTION_QUEUE"] == "1"
-  module QueuePatch
-    # Add +element+ to the queue.  Never blocks.
-    def add(element)
-      puts "::group::##{Process.pid} Adding element to the queue"
-      puts Thread.current.backtrace.first(30).join("\n")
-      puts "::endgroup::"
-      super
-    end
-
-    # If +element+ is in the queue, remove and return it, or +nil+.
-    def delete(element)
-      puts "::group::##{Process.pid} Delete element from the queue"
-      puts Thread.current.backtrace.first(30).join("\n")
-      puts "::endgroup::"
-      super
-    end
-
-    # Remove all elements from the queue.
-    def clear
-      puts "::group::##{Process.pid} Clear all elements from the queue"
-      puts Thread.current.backtrace.first(30).join("\n")
-      puts "::endgroup::"
-      super
-    end
-
-    private
-
-    def remove
-      puts "::group::##{Process.pid} Removing element from the queue"
-      puts Thread.current.backtrace.first(30).join("\n")
-      puts "::endgroup::"
-      super
-    end
-  end
-
-  ActiveRecord::ConnectionAdapters::ConnectionPool::Queue.prepend(QueuePatch)
-end